It is proposed to advance the state-of-the-art of automatic microscopy incorporating several new features viz. solid state linear arrays, micro-processors and fractionally stepped stepper motors. It is planned to demonstrate the value of this approach in a specific application, that of cytogenetics, by testing a stand-alone automatic metaphase finding microscope just being completed both as is and with extended capabilities. This is a request for a renewal of a project started just one year ago, under a two year grant, which has funded the construction of such a microscope. It is proposed to test the basic instrument first, both in-house and in the field as well as to develop further three aspects: the high performance digital stage, automatic focusing and use of the microscope as an image digitizer. Both functions are to operate at high power or resolution (at N.A. 1.4 oil immersion resolution). The project involves cooperation of four laboratories; the Tufts Quantitative Image Analysis Lab, the C.S. Draper Laboratory Inc., the Cytogenetics Laboratory of the New England Medical Center Hospital and the Eunice Kennedy Shriver Center Cytogenetics Laboratory. At the Eunice Kennedy Shriver Center the application will be largely in amniocentesis work, an activity of growing importance for which automated metaphase finding is particularly important to be able to cope with the growing work load.